The objective of this project is to understand how tactile patterns are perceived by human subjects. The project will focus on the processing of spatiotemporal patterns and the interactions that occur between spatial patterns presented to the same and to separate locations. The results from the psychophysical measures will be related to neurophysiological studies of peripheral and central responses to tactile stimuli. The tactile patterns will be generated by several types of displays. One of these is the dense array which consists of 400, independently controlled tactors. This display will be used to generate and test subjects' sensitivity to drilling, sinusoidal spatiotemporal patterns of various wavelengths and frequency. The array will also be used to activate selectively different populations ofmechanoreceptors. The effect of such variables as contactor penetration, velocity, and site of stimulation on spatial and intensive sensitivity will also be measured. Using the dense array as well as arrays from the Optacon, a reading aid for the blind, temporal interactions such as masking, response competition, and temporal integration will be examined. The project will also be concerned with the effect of pattern movement on interactions between tactile stimuli and between tactile and visual stimuli. One of the aims of the project is to compare results obtained with tactile stimuli to studies conducted with visual and auditory stimuli. The results from these projects will be relevant to the development of cutaneous communication systems for the deaf, blind, and deaf-blind. The results will also be relevant to the effects that intermediate surfaces such as surgical gloves have on tactile sensitivity and to the measurement and understanding of neurological problems.